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Hello! from Treasure Coast Florida

WREKS

Jetboaters Lieutenant
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Port Saint Lucie, Florida
Boat Make
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Year
2007
Boat Model
SX
Boat Length
23
Good to be here. I have received and continue to receive much helpful and encouraging information from all the members contributing to the forums. I hope to be one of those members.

I love the water and boats. I got a jet boat for two reasons: I would not destroy props like I did on lakes up in Wisconsin and I thought it would be friendlier toward the creatures like manatees below the surface. I got twin engines for power but also for some assurance to get back to shore if one failed . Most of our (my wife and I) cruising has been on the Indian River Lagoon. Our boat is twelve years old but engines have less that 100 hours. Of course, we do not use our boat enough; but when we want to and we cannot-that is what this post is about.

Last time we went out, the port engine had the 'milky oil syndrome', and starboard engine was going into limp-mode after high temperature shutdown. I determined, the engines would have to be removed, one at a time, to look for the problems. The 2007 SX230HO is not easily worked on without pulling engines. I had never done this, so over the course of several months, I was able to fabricate a gantry crane in order to remove and reinstall the engines.

On the port engine, I replaced the cooling water pipe O-ring . I also eliminated the sand and corrosion in the manifolds and exhaust pipes. I did not remove the port cylinder head. But I think I may have to. The following will explain why.

I then took on the starboard engine overheating problem. While running on the hose, it was overheating after a few minutes and dropping into limp mode. I pulled the engine, replaced the engine and exhaust thermos switches because they tested out of spec, reinstalled the engine, and started it. That did not matter. It was still overheating. What finally convinced me to pull the engine AND remove the cylinder head occurred while running it on the hose again. I choose a spot on the cylinder head to take a temperature reading. That spot was a little nub of metal just above the exhaust port for Cylinder #1 and under the valve cover. Just before dropping into limp mode, the engine temperature rose from 150° F to 216° F in less than a minute. I got this reading using a IR temperature sensor. To make sure that the reading was not some sort of aberration, I started the port engine and took the reading at the same place on the cylinder head. It was and stayed below 140°F. I was convinced. The engine had to come out and the head had to come off. I did not want to do this, but I did not see any other way.

The cylinder head was clogged both above and below the head gasket. The water jackets surrounding the cylinders were impacted with a sand mix close to cement, especially around cylinders #1 and #2. I used pic tools and vinegar to loosen the buildup. I thought of what it takes a dentist to remove plaque below the gum line. Here are some before and after pictures. I hope this takes care of the overheating problem.

I always thought saltwater was the culprit. Now I am beginning to think that once sand gets forced into the water jackets, it is not easily removed, especially after building up over the years. Shallow water encounters giving the cooling system any opportunity to vacuum the bottom seem to be a very normal occurrence for most of us. I will definitely try the high pressure, closed loop cleaning suggested by CrankyGypsy. Like many others, I have had overheats from the very beginning. And I know the YDS does not register but a few of them.

I have to put the engine back together and see if there is any change. One must not get too confident. I hope these pictures come through. I have a question to ask. I hope it does not sound like a dumb one. The existing head gasket is a multilayer steel gasket. Do you think I could temporarily reuse it just in NoWake mode to see if my overheat issue is resolved? Thank you for any all input.

Starboard cyclinder head-clogged on intake side .JPGStarboard cylinder block-water jackets clogged.JPGStarboard cylinder block with head gasket.JPGStarboard cylinder block with head gasket.JPGStarboard cylinder head-cleaned up.JPGStarboard cylinder head-cleaned up.JPGStarboard cylinder block water jackets-cleaned up.JPG
 

buckbuck

Jetboaters Admiral
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2008
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X
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Great write up @WREKS
Welcome to the forum. We have another member going through the same thing right now and had success clearing the salt with a concoction of dissolving chemicals and the @CrankyGypsy method. I admire your taking on this adventure.
Perhaps some other guys who have more rebuild experience than I will comment on the head gasket.
 

Dean P

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@WREKS Welcome to the forum :Welcome:. Lots of good info here to help keep you on the water. We love pictures! Please share often. Impressive read! Thanks for sharing. Good luck.
 

CrankyGypsy

Jetboaters Captain
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Challenger
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Good work! Your pics show the problem of Yamaha's flush system: the amount of water it allows in is inadequate and it doesn't distribute it well (to cylinder 1). I'd argue the issue of build-up (and subsequent overheat) is not caused specifically by "salt," but rather "salt water" which contains an extremely high amount of calcium relative to fresh water. the calcium becomes the binder/insulator, but the blame for any aluminum corrosion still goes to the salt bound to it. keep in mind that I found that one of Salt-Away's competitors (Hammerhead) did a poor job of breaking down the calcium compared to sulfamic acid. again, the Yamaha flush system allows an inadequate amount of water into the engine, so build-up will continue no matter what you use - I'd recommend a closed loop flush at least every two years for anyone frequently in salt: I continued to use Salt-Away following my closed loop flush and was amazed how much gunk came out after one season.

ADD: I'd also recommend my thermostat mod - drill a second hole 180* of the one on the thermostat face to allow water to drain through during driveway flushes. the original top hole will continue to allow air to escape and the bottom hole will help reduce build-up within the housing.

EDIT: corrected Salt-Away to Hammerhead.
 
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WREKS

Jetboaters Lieutenant
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Year
2007
Boat Model
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Boat Length
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Reinstalled Starboard engine after chiseling out sediment/salt deposited in cylinder head, exhaust manifolds, and water jackets in cylinder block. Reused head gasket. Ran on hose in limp and nowake. No leaks; no overheats. So far so good.
 

J-RAD

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Welcome! I hope you make it back on the water soon.
 

WREKS

Jetboaters Lieutenant
Messages
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Location
Port Saint Lucie, Florida
Boat Make
Yamaha
Year
2007
Boat Model
SX
Boat Length
23
Welcome! I hope you make it back on the water soon.
Thank you, J-Rad. I am in process of doing same thing to Port Engine-cleaning our sediment/salt deposits mainly in cylinder block water jackets. Engines only have 100 hours, but got pretty silted and salted from backing against a sand bar once +. Bad idea, sucks up crud that flushing and Salt-Away cannot deal with.
 

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